A private corporation called Celera Genomics used a different method, called "shotgun sequencing." Celera randomly broke the entire genome apart into many different sizes. For example, pieces might be 2,000, 10,000, 50,000, and 150,000 base pairs long. Each individual base pair in the genome was present in many (at least a dozen) overlapping copies. All of the pieces were then sequenced, and when the sequence information was fed into a computer, the overlapping sequences were used to reconstruct the whole genome.